You have to come to terms with the fact that the aged body is less likely to tolerate night shifts and all-nighter study sessions than a younger one.
I studied harder, longer than in any of my previous life during M1/M2, but kept a much more normal schedule (rarely got up before 6 or 7, was typically in bed by 11:30). I didn't do a SINGLE all-nighter, while 20 year old me might have if I was in that space.
It can be annoying to take orders from someone half your age, but that's true of any job. I will say that the hierarchy is very concrete in medical education so I felt it more keenly. I am regularly lectured on my previous career (RN) by people who have only been in healthcare for a couple years, but they are higher on the totem pole so it's expected that they are the experts.
The biggest thing I'd say is that despite me being a nontrad I received amazing interview invites and had good conversations with program directors who made it clear that my age was not seen negatively. I don't think anyone was comfortable saying my age was a positive, but they did frame my life experiences as big pluses.